The present invention relates to a method for joining together operative steel pipes for conveying fluids such as gas, water or the like.
As is known, in pipes for conveying fluids such as gas or water, it may happen that a section of the pipe must undergo maintenance or even be replaced in order to avoid the loss of fluid conveyed by the pipe or simply be removed in order to allow insertion in this pipe of a given connection piece, such as a branch-off piece, a pipe section, a valve or the like. These operations for the maintenance and repair of damaged pipes or for replacing a pipe section with a different tubular connection piece require the use of complex and costly means and/or operations since this gas or water conveying pipe is normally situated underground and the section to be replaced must, among other things, be isolated with interception of the fluid upstream and downstream thereof.
The object of the present invention is therefore to provide a method for joining together pipes for conveying fluids such as gas, water or the like, by means of which it is possible to repair in a simple, efficient and low-cost, but in particular reliable manner a damaged pipe section and restore normal operation thereof effectively or replace a pipe section with another connection piece such as a branch-off piece, a valve or the like.
This object is achieved with the present invention by means of a method for joining together pipes for conveying fluids, characterized by the following steps:
a) identifying a pipe section to be replaced and intercepting, using suitable stopper means, the fluid flow inside the pipe upstream and downstream of this pipe section;
b) removing the pipe section to be replaced so as to obtain upstream and downstream thereof two pipe sections;
c) inserting stopper means for protection against any seepage of fluids (gas or liquids) and therefore possible initial leakage or dripping of water, oil, etc., and removing by means of milling from the end of the pipe section any burrs or sharp edges which may damage the seal and then mounting on each pipe section a sliding steel sleeve provided with sealing means;
d) removing said protective stopper means from the pipe sections and positioning between them a new connection piece, such as a pipe section, a branch-off piece, a valve or the like;
e) displacing said sliding sleeves on these pipe sections so that the seal also embraces this new connection piece;
f) welding these sliding sleeves to these pipe sections and to this connection piece.